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@@ -1,124 +1,124 b'' | |||
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1 | 1 | """Latex filters. |
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2 | 2 | |
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3 | 3 | Module of useful filters for processing Latex within Jinja latex templates. |
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4 | 4 | """ |
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5 | 5 | #----------------------------------------------------------------------------- |
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6 | 6 | # Copyright (c) 2013, the IPython Development Team. |
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7 | 7 | # |
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8 | 8 | # Distributed under the terms of the Modified BSD License. |
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9 | 9 | # |
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10 | 10 | # The full license is in the file COPYING.txt, distributed with this software. |
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11 | 11 | #----------------------------------------------------------------------------- |
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12 | 12 | |
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13 | 13 | #----------------------------------------------------------------------------- |
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14 | 14 | # Imports |
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15 | 15 | #----------------------------------------------------------------------------- |
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16 | 16 | import re |
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17 | 17 | |
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18 | 18 | #----------------------------------------------------------------------------- |
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19 | 19 | # Globals and constants |
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20 | 20 | #----------------------------------------------------------------------------- |
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21 | 21 | |
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22 | 22 | LATEX_RE_SUBS = ( |
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23 | 23 | (re.compile('\033\[[0-9;]+m'), ''), # handle console escapes |
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24 | 24 | (re.compile(r'\.\.\.+'), r'\\ldots'), |
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25 | 25 | ) |
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26 | 26 | |
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27 | 27 | # Latex substitutions for escaping latex. |
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28 | 28 | # see: http://stackoverflow.com/questions/16259923/how-can-i-escape-latex-special-characters-inside-django-templates |
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29 | 29 | |
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30 | 30 | LATEX_SUBS = { |
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31 | 31 | '&': r'\&', |
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32 | 32 | '%': r'\%', |
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33 | 33 | '$': r'\$', |
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34 | 34 | '#': r'\#', |
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35 | 35 | '_': r'\_', |
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36 | 36 | '{': r'\{', |
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37 | 37 | '}': r'\}', |
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38 | 38 | '~': r'\textasciitilde{}', |
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39 | 39 | '^': r'\^{}', |
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40 | 40 | '\\': r'\textbackslash{}', |
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41 | 41 | } |
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42 | 42 | |
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43 | 43 | |
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44 | 44 | #----------------------------------------------------------------------------- |
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45 | 45 | # Functions |
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46 | 46 | #----------------------------------------------------------------------------- |
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47 | 47 | |
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48 | 48 | __all__ = ['escape_latex', |
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49 | 49 | 'strip_math_space'] |
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50 | 50 | |
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51 | 51 | def escape_latex(text): |
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52 | 52 | """ |
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53 | 53 | Remove ansi codes and escape characters that may conflict with latex. |
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54 | 54 | |
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55 | 55 | Parameters |
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56 | 56 | ---------- |
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57 | 57 | text : str |
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58 | 58 | Text containing characters that may conflict with Latex |
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59 | 59 | """ |
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60 |
text = ''.join( |
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60 | text = ''.join(LATEX_SUBS.get(c, c) for c in text) | |
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61 | 61 | for pattern, replacement in LATEX_RE_SUBS: |
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62 | 62 | text = pattern.sub(replacement, text) |
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63 | 63 | |
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64 | 64 | return text |
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65 | 65 | |
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66 | 66 | |
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67 | 67 | def strip_math_space(text): |
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68 | 68 | """ |
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69 | 69 | Remove the space between latex math commands and enclosing $ symbols. |
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70 | 70 | This filter is important because latex isn't as flexible as the notebook |
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71 | 71 | front end when it comes to flagging math using ampersand symbols. |
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72 | 72 | |
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73 | 73 | Parameters |
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74 | 74 | ---------- |
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75 | 75 | text : str |
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76 | 76 | Text to filter. |
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77 | 77 | """ |
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78 | 78 | |
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79 | 79 | # First, scan through the markdown looking for $. If |
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80 | 80 | # a $ symbol is found, without a preceding \, assume |
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81 | 81 | # it is the start of a math block. UNLESS that $ is |
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82 | 82 | # not followed by another within two math_lines. |
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83 | 83 | math_regions = [] |
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84 | 84 | math_lines = 0 |
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85 | 85 | within_math = False |
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86 | 86 | math_start_index = 0 |
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87 | 87 | ptext = '' |
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88 | 88 | last_character = "" |
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89 | 89 | skip = False |
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90 | 90 | for index, char in enumerate(text): |
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91 | 91 | |
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92 | 92 | #Make sure the character isn't preceeded by a backslash |
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93 | 93 | if (char == "$" and last_character != "\\"): |
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94 | 94 | |
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95 | 95 | # Close the math region if this is an ending $ |
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96 | 96 | if within_math: |
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97 | 97 | within_math = False |
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98 | 98 | skip = True |
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99 | 99 | ptext = ptext+'$'+text[math_start_index+1:index].strip()+'$' |
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100 | 100 | math_regions.append([math_start_index, index+1]) |
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101 | 101 | else: |
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102 | 102 | |
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103 | 103 | # Start a new math region |
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104 | 104 | within_math = True |
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105 | 105 | math_start_index = index |
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106 | 106 | math_lines = 0 |
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107 | 107 | |
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108 | 108 | # If we are in a math region, count the number of lines parsed. |
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109 | 109 | # Cancel the math region if we find two line breaks! |
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110 | 110 | elif char == "\n": |
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111 | 111 | if within_math: |
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112 | 112 | math_lines += 1 |
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113 | 113 | if math_lines > 1: |
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114 | 114 | within_math = False |
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115 | 115 | ptext = ptext+text[math_start_index:index] |
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116 | 116 | |
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117 | 117 | # Remember the last character so we can easily watch |
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118 | 118 | # for backslashes |
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119 | 119 | last_character = char |
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120 | 120 | if not within_math and not skip: |
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121 | 121 | ptext = ptext+char |
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122 | 122 | if skip: |
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123 | 123 | skip = False |
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124 | 124 | return ptext |
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